Suspension, Brakes and Tires Discussion, Warpped Rotors Again in Item Specific Cadillac Discussion; 98 Eld Rear Rotors Warpped Again. Had The Original Rotors Turned With New Pads From Napa And With-in 5000 Miles ...

Warpped Rotors Again

98 Eld Rear Rotors Warpped Again. Had The Original Rotors Turned With New Pads From Napa And With-in 5000 Miles Vibration Returned. Replaced Rear Rotors (napa) And Within 2000 Miles Vibration Returned. Is Mechanical, Applied Emerg. Brake And Will Vibrate. Any Help Will Be Helpfull. Thanks Eldorado98

Re: Warpped Rotors Again

has it rained lately? my old mechanic, who has since gone on, told me once that you can put brand new rotors on a car, go riding around and theyll get real hot and you hit a puddle of water it can warp the rotors. i dont know your problem though, just something to think about.

Re: Warpped Rotors Again

Originally Posted by 93fleetwoodlowlow

has it rained lately? my old mechanic, who has since gone on, told me once that you can put brand new rotors on a car, go riding around and theyll get real hot and you hit a puddle of water it can warp the rotors. i dont know your problem though, just something to think about.

If that were true, we'd all have warped rotors. Do you think the manual says to avoid puddles with your new Cadillac?

Re: Warpped Rotors Again

Originally Posted by ELDORADO98

98 Eld Rear Rotors Warpped Again. Had The Original Rotors Turned With New Pads From Napa And With-in 5000 Miles Vibration Returned. Replaced Rear Rotors (napa) And Within 2000 Miles Vibration Returned. Is Mechanical, Applied Emerg. Brake And Will Vibrate. Any Help Will Be Helpfull. Thanks Eldorado98

Check the rear calipers for freedom of movement. If a caliper hangs-up most of the braking pressures and heat is applied to one side of that rotor and very little to the other side. The rears are solid (non-vented) rotors that are more susceptible to warping than the vented front rotors. A sticking rear caliper was the problem on my ’97 SLS’s rear brakes causing one of the rotors to warp and vibrate during braking.

Re: Warpped Rotors Again

One thought is that, no, drilled rotors won't correct the problem. Before the rotors warp, how does the car stop? On a hard brake, does the ass end want to walk out? If so, it could be a porportioning issue.

That's awfully low mileage for brake issues. (My car's clock just hit 70k. I thought I had about 70% left on the fronts, but I checked the other day and it's over 79% left.)

Did you buy the car new? If you bought it used, it's a coin toss as to whether or not it's a rebulilt wreck, and that could cause issues. Carfax reports don't mean diddily squwat.

Do you use the emergency brake when you park? Setting the "parking" brake is something left over from the 40 and 50's, and with modern automatics--other than cases where the transmission locks from extreme inclines--it defies logic as to why anyone would want to set the emergency brake when parking. I find the puddle problem hard to buy into, and I point this out because I don't want do sound condridictry: I have no clue as to whether or not it would cause such a problem, but putting a mojo clamp on an area on a warm peice of metal, then allowing it to cool doesn't seem to be sound mechanical reasoning. Again, I'm not saying this is the cause of the problem, but if you ponder the thought, it seems as if such an operating condition could make one wonder. If you set the brake, one way you could conduct a test is get them turned, quit setting the brake, see what happens. If the problem goes away, you can post the results.

It could be the parts. I don't know how they rank now but in the old days, NAPA was top quality parts. Many people claim that Raybestos brake parts exceede the quality of OEM parts.

Were the back brakes done because of warped rotors or because of shot pads? If that's the case, it isn't a parts issue

Re: Warpped Rotors Again

Originally Posted by 93fleetwoodlowlow

he didnt say it happens everytime, just that it has happened before.

Maybe I'm being anal, but the way you worded your post I took it to mean we should all stay out of puddles for fear of warping our rotors.
"you can put brand new rotors on a car, go riding around and theyll get real hot and you hit a puddle of water it can warp the rotors."

Eldorado98, Are you sure they are warped? Has anyone put a dial gage to them off of the car to confirm?
Warping is caused by excessive heat build up, which softens the metal and can allow it to be disfigured. This can result in wheel shimmy during braking. Pads should lightly ride on the rotors. If they are truly warped, I would look for something causing the pads not to release correctly as mentioned previously. The proportioning valve perhaps, someone here discovered a faulty brake line when they couldn't get a caliper to release. Does your E-brake release completely? Could be a sticking brake cable. keep us informed.

Re: Warpped Rotors Again

when you had the work done on the car were the brakes "burnished" corectly ? or did someone toss the parts ona nd turned over the keys and the vehicle resumed normal use? burnsihed is a repeated firm application of brakes from 45 and 60 mph whent he brakes are put on to get some heat in boath pads and rotors and to get everyone mated just right ....

Sometimes vehciles that didnt get there brakes burnished corectly will tend to "warp" rotors...

Recently ive learned that most of the time "warpage" isnt there but rather a funky buildup and heat checking fo the rotor takes place , which causes the pedal to pulse ....things from crappy pads or rotors , to too thin of a rotor , to raceing mishaps causeing these funny buildups ...i havent been in a shop to verify what ive found but the idea seems to hold water from my experence

cross drilled rotors will only incrase your stopping distance when cold ...these cars never get used hard enough to need cross drilled rotors , if they ddi you would use a set of front tires every week ....

also check to make sure that the rust in between the rotor and hub is removed , this can cause balance issues and odd wearing of the rotor ,esp if the stock rotor was removed , turned and replaced and wasnt put in the same position it came off in and rust wasnt removed fromt he mateing surface between rotor and hub

Re: Warpped Rotors Again

I owned two Eldo's 89 & 99. This is common to me but over time, between rainy season and summer. Normal braking then a sudden splash on the rotor over time will cause the rotor to warp. I have the problem now and had before. One problem is that there is no brake splash shield on the inside of the rotor face , like other Gm vehicles. My surb has them and I dont have this issue that quick. Each time this occurs I remove the rotor and take down and turn . Once on the lathe you can see the hi spots of maybe 30 thousanths or so then the cutter will begin truing up the entire rotor.. The Firestone stores recommend spraying some type of bare metal dresser that appears to me like silver spray paint but its not... Install new pads and I am done. I have only had this issue with the front, why not the rear? Chemosabe.

Re: Warpped Rotors Again

I recently got my rotors machined and new pads installed, but instead of aftermarket pads (that are often hard and 'long lasting' i.e. wear resistant) I went with OEM pads that are softer and wear faster. I figured, let the pads take the wear and spare the rotors. (since they're getting pretty thin already)

I decided, long ago, that I'd always go OEM when it comes to brakes because friction systems are a tricky thing and the rotors/pads need to be well matched or there will be problems (noise/vibration/wear/warpage)

ps I think drilled or slotted rotors will warp even quicker. (especially for heavy cars like ours)

pps That puddle story is true....sometimes. If brakes are really really hot and you hit the water for the right depth, duration and temperature, it will cause the part of the metal in contact with the water to "quench" or shrink, resulting in nonuniform temperature distributions. And if the resulting thermal gradient is large enough, the rotor will deform/warp and theoretically even crack. (and even if it doesn't, thermally cycling it in this manner over time will eventually lead to warpage)